The Opponents List rows totals issue is written up for the developers to address.
HMT-4991: Opponents List view totals row not updating with filters
If you want to be notified when it is fixed please
send an email via the 'Contact Support' link and include "Notify Me When HMT-4991 Is Resolved" in the subject line and body of the email.
The Opponent's List has to filter/scan through 404 GB of mined hands each time that loads or you change a filter. It might not be using more RAM to load that view but it has to scan the entire database before it can load/filter that view. HM3 typically takes about 6 GB per 1 million hands, so your 404 GB database is approximately 67 million hands total that HM3 has to scan (even though your Stars hero only has 863,146 hands) before it can load that view.
Please try creating a new database and import only your own played hands from C:\HM3Archive and C:\HM2Archive and see how the new smaller database without mined hands performs. If the new smaller database performs better than you know the cause was a result of the enormous database size.
Note: As datamining is against the rules at all of the sites we support we can not provide technical support with hands customers didn't actually play in. If you are caught by your site using mined hands in the database you play with you could face action from them including having your account frozen. If you have mined hands we suggest you only use those in a separate database for player pool analysis and review, that you do not use when playing. Your database you use when playing should only contain your own played hands.